As a new kind of material, a metamaterial is formed by a substrate made of a non-metallic material and a plurality of man-made microstructures attached on a surface of the substrate or embedded inside the substrate. The substrate may be virtually divided into a plurality of cubic substrate units arranged in a rectangular array shape, with each of the substrate units being attached with one man-made microstructure to form one metamaterial unit. Correspondingly, just like a crystal which is formed by numerous crystal lattices arranged in a certain manner, the whole metamaterial consists of hundreds of or millions of or even hundreds of millions of such metamaterial units. The man-made microstructures may either be the same or not be totally the same for each of the metamaterial units. Each of the man-made microstructures is a cylindrical or flat metal wire that forms a certain geometrical pattern, for example, a metal wire that forms a circular shape, an “l” shape or the like.
Due to presence of the man-made microstructures, each of the metamaterial units presents an equivalent dielectric constant and an equivalent magnetic permeability that are different from those of the substrate. Therefore, the metamaterial comprised of all the metamaterial units exhibits special response characteristics to the electric field and the magnetic field. Meanwhile, by designing the man-made microstructures into different structures and shapes, the equivalent dielectric constant and the equivalent magnetic permeability of the metamaterial units and, consequently, the response characteristics of the whole metamaterial can be changed.
Accordingly, there is a need in the art to provide a metamaterial that can gather planar electromagnetic waves or even converge them to a point just like a lens which converges parallel light rays to a single point. Unfortunately, this need has not been satisfied in the art.